void printInfo() {
  print('我是一个自定义方法');
}

String printUserInfo() {
  return 'this is str';
}

List getList() {
  return ['111', '222'];
}

void main() {
  print('调用系统内置的方法');
  printInfo();
  int getNum() {
    var myNum = 123;
    return myNum;
  }

  var n = getNum();
  print(n);
  var str = printUserInfo();
  print(str);
  print(getList());
}
